Table of Contents
Molecular Biology International
Volume 2011, Article ID 876021, 12 pages
http://dx.doi.org/10.4061/2011/876021
Research Article

Antiproliferative, Ultrastructural, and Physiological Effects of Amiodarone on Promastigote and Amastigote Forms of Leishmania amazonensis

1Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Avenida Carlos Chagas, 373, CCS, Ilha do Fundão, 21941-902 Rio de Janeiro, Brazil
2Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Brazil
3Instituto Venezolano de Investigaciones Cientificas, Caracas, Venezuela
4Instituto Nacional de Metrologia, Normalização e Qualidade Industrial (Inmetro), 20261-232 Rio de Janeiro, Brazil
5Pólo Avançado de Xerém, Universidade Federal do Rio de Janeiro, 25250-470 Rio de Janeiro, Brazil

Received 18 January 2011; Revised 1 March 2011; Accepted 14 March 2011

Academic Editor: Kwang Poo Chang

Copyright © 2011 Sara Teixeira de Macedo-Silva et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Amiodarone (AMIO), the most frequently antiarrhythmic drug used for the symptomatic treatment of chronic Chagas' disease patients with cardiac compromise, has recently been shown to have also specific activity against fungi, Trypanosoma cruzi and Leishmania. In this work, we characterized the effects of AMIO on proliferation, mitochondrial physiology, and ultrastructure of Leishmania amazonensis promastigotes and intracellular amastigotes. The IC50 values were 4.21 and 0.46  𝜇 M against promastigotes and intracellular amastigotes, respectively, indicating high selectivity for the clinically relevant stage. We also found that treatment with AMIO leads to a collapse of the mitochondrial membrane potential ( Δ Ψ 𝑚 ) and to an increase in the production of reactive oxygen species, in a dose-dependent manner. Fluorescence microscopy of cells labeled with JC-1, a marker for mitochondrial energization, and transmission electron microscopy confirmed severe alterations of the mitochondrion, including intense swelling and modification of its membranes. Other ultrastructural alterations included (1) presence of numerous lipid-storage bodies, (2) presence of large autophagosomes containing part of the cytoplasm and membrane profiles, sometimes in close association with the mitochondrion and endoplasmic reticulum, and (3) alterations in the chromatin condensation and plasma membrane integrity. Taken together, our results indicate that AMIO is a potent inhibitor of L. amazonensis growth, acting through irreversible alterations in the mitochondrial structure and function, which lead to cell death by necrosis, apoptosis and/or autophagy.